P0070 OBD-II Trouble Code: Ambient Air Temperature Sensor Circuit

P0070 code definition

Depending on the type of vehicle these are some related OBD-II Diagnostic Trouble Codes:

P0071: Ambient Air Temperature Sensor Range/Performance

P0072: Ambient Air Temperature Sensor Circuit Low Input

P0073: Ambient Air Temperature Sensor Circuit High Input

What the P0070 code means

The Power Control Module (PCM) receives information from the ambient air temperature sensor. With this information, the Power Control Module (PCM) is able to monitor and balance the ambient air temperature with the intake air temperature. If the Power Control Module (PCM) reads that the ambient air temperature and intake air temperature are not at the correct levels, the PCM will store the P0070 code and trigger the Check Engine Light to illuminate.

What causes the P0070 code?

The following could cause the P0070 trouble code:

Ambient air temperature sensor that has failed or one that is faulty

Wires that have broken or shorted out

Electric circuitry that is corroded

Connector that is corroded

An ambient air temperature harness that is open or shorted

Foreign objects covering the sensor

What are the symptoms of the P0070 code?

Most commonly, the only indication that there is a fault in the ambient air temperature sensor will be the Check Engine Light. Another symptom that is less likely is the climate control system (heat and/or air condition controls) will not work properly.

How does a mechanic diagnose the P0070 code?

The first step in diagnosing the P0070 trouble code is to use an OBD-II scanner and making a record of the freeze frame data as well as all trouble codes that have been stored.

Next, the ambient air temperature sensor wiring and its connector need to be checked for shorts or opens in the wires, bare wires and/or corrosion in the connector. It is also important to check for debris that could be covering the sensor.

If all of these components are normal and working properly, any and all codes that were present during the original scan should be cleared, and the vehicle test driven.

If during the test drive, the P0070 trouble code returns, the ambient air temperature sensor will need to be replaced.

If the P0070 trouble code does not come back immediately, this could mean that there is an intermittent problem related to the voltage going to the PCM and further. In this instance, a more extensive diagnosis process would be required.

It is very rare, but possible that there is an issue with the Power Control Module (PCM) if all of the above diagnostic measures do not resolve the P0070 trouble code.

Common mistakes when diagnosing the P0070 code

Replacing the ambient air temperature sensor is not always necessary to fix the problem. A common mistake is for the ambient air temperature sensor to be replaced without first checking the wires and connector for defects.

How serious is the P0070 code?

This code is not considered to be a serious one since it will not cause drivability problems or prevent the car from running properly. In some cases, the climate control system (heat and/or cold air condition controls) will not work properly, which may be uncomfortable depending on weather conditions.

What repairs can fix the P0070 code?

Repairing broken or shorted wires

Cleaning corrosion from connector and/or electric circuitry

Replacing the ambient air temperature sensor

Additional comments for consideration regarding the P0070 code

In most cases, it will be required to replace the ambient air temperature sensor in order to clear the P0070 trouble code. However, it is always important to first check the wiring, connectors, and harness before concluding that the issue is the ambient air temperature sensor.

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